1. Field of Use
This invention relates to liquid tank anti-theft devices for placement within a tank filler tube which prevents insertion of a siphon tube or other liquid removal means in the tank.
2. Description of the Prior Art
Some prior liquid tank anti-theft devices have inherent disadvantages in that they are only with some difficulty permanently secured in the tank filler tube, which securement is essential to prevent their unwarranted removal. For Example, the device described in U.S. Pat. No. 2,107,600, issued to Darms on Feb. 8, 1938, and entitled "Gas Keeper", can only be secured by bending a plurality of tongues into place under the tank filler aperture using a screw driver or the like. Those devices which may be secured to the filler tube merely by insertion therein and thus, not having the disadvantages of Darms, are typically of construction that is somewhat complicated and thus expensive. For example, the device in U.S. Pat. No. 2,147,755, issued to Roberts on Feb. 21, 1939, and entitled "Siphon and Theftproof Gas Tank Cover", is secured by a ratchet upon its insertion into the tank filler tube. Roberts has the further disadvantage of requiring its own tank filler tube cap. The filler cap supplied with a Roberts device intended to be retrofitted to an automobile must have a seal for preventing release of gasoline vapors therethrough complying with the appropriate government standards. Because the automobile's original complying cap may not be used on a Roberts device, the retrofit of Roberts on an auto is needlessly expensive. Still other anti-theft devices may not be used on all of the several different filler tube apertures. In automobiles, for example, holes in the spacers of tank fill tube apertures are flared inwardly, that is, towards the fuel tank, for strength, and the extent of the inward flare varies with the auto manufacturer. Many antisiphon devices, such as that shown in U.S. Pat. No. 2,145,759, issued to Fellows on Jan. 31, 1939, and entitled "Antisiphon Devices for Fuel Tanks", have rigid locking lugs for securing the device to an aperture. These rigid lugs may only be used on an aperture with one flare depth, limiting the device's applicability to autos having apertures with that flare depth.